644016 has 20 divisors (see below), whose sum is σ = 1663832. Its totient is φ = 214656.

The previous prime is 644009. The next prime is 644029. The reversal of 644016 is 610446.

644016 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (21) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 643983 and 644001.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6661 + ... + 6756.

2⁶⁴⁴⁰¹⁶ is an apocalyptic number.

It is an amenable number.

644016 is an abundant number, since it is smaller than the sum of its proper divisors (1019816).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644016 is a wasteful number, since it uses less digits than its factorization.

644016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13428 (or 13422 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 644016 is about 802.5060747434. The cubic root of 644016 is about 86.3572662472.

The spelling of 644016 in words is "six hundred forty-four thousand, sixteen".